Recently, image-recording materials, in particular, materials for forming color images have been a mainstream, and specifically, recording materials for inkjet system, recording materials for a heat-sensitive transfer system, recording materials of electrophotographic system, transfer type silver halide photosensitive materials, printing inks, and recording pens have been widely used. In addition, in imaging elements such as CCD for imaging devices, and in LCD or PDP for displays, color filters have been used for recording and reproducing a color image.
In this color image recording materials or color filters, in order to reproduce or record full color images, dyes and pigments of three primary colors of a so-called subtractive color mixing method or additive color mixing method are used, but there is no fast colorant having absorption characteristics can realize a preferred color reproduction range, and can withstand a variety of operating conditions. Thus, improvements are strongly desired.
An inkjet recording method is rapidly spread and more developed because material cost is low, high-speed recording is feasible, a noise is low while recording is performed, and color recording is easy.
The inkjet recording method includes a continuous manner that continuously disperses a liquid drop and an on-demand manner that disperses a liquid drop according to an image information signal as the inkjet recording method, and a discharging manner includes a manner that discharges a liquid drop by applying pressure by a piezo element, a manner that discharges a liquid drop by generating bubbles in ink by heat, a manner that uses an ultrasonic wave, and a manner that absorbs a liquid drop by electrostatic force and discharge it.
Further, an aqueous ink, an oily ink or a solid (melt type) ink is used as an ink for inkjet recording.
A colorant used in ink for inkjet recording needs to ensure favorable solubility or polydispersity to a solvent, recording at a high concentration, favorable colors, fastness to light, heat, and active gas (NOx, SOx other than oxidative gas such as ozone, or the like) in an environment, excellent fastness to water or chemicals, good settlement to an image-receiving material, low spreading, excellent preservation as ink, non-toxicity, high purity, and availableness at low price.
However, it is very difficult to seek a dye that satisfies these requirements at a high level. In particular, a colorant having a good cyanide color, a colorant having fastness to light, humidity, and heat, among them, when printing onto the water-like material having an ink receiving layer containing a porous white inorganic pigment particles, a colorant having fastness to the oxidative gas such as ozone in the environment is strongly demanded, and at the same time a colorant having compatibility of the ink storage stability is strongly demanded as described below.
A colorant structure of cyanide used in such ink for inkjet recording includes phthalocyanine, anthraquinone, triphenylmethane, and the like, and the phthalocyanine compound having excellent color and light fastness has been used. However, because the structure does not have sufficient fastness to the oxidative gas, especially ozone, and the ink stability is not satisfied, improvement is demanded.
A phthalocyanine dye represented by Direct Blue 87 or Direct Blue 199 currently, commonly and widely used and also described in the publication, etc., is characterized by having an excellent light resistance compared with the magenta or yellow, but it tends to occur problems caused by the solubility of the dye. For example, the dissolution failure occurred at the time of manufacturing causes a manufacturing trouble, or the insoluble material precipitated when preserving or using products causes problems, too. In particular, in the inkjet recording described above, since the storage stability such as precipitation of the dye is poor, there is a problem in that clogging of the print head or discharge failure may occur, or the printed image may be significantly deteriorated.
Further, it becomes a significant problem in that the colorant is easily discolored by oxidative gases such as ozone, which is often taken as recent environmental issues, and the print density is significantly decreasing.
Currently, the usage field of an inkjet recording is rapidly expanding, and the inkjet recording becomes to be more and more widely used in the future households, SOHO, the business field, and the like, which results in contact with a variety of using conditions or using environment. As a result, there occurs a problem in the ink storage stability due to the poor solubility of the cyanide dye ink, or a problem of fading of the printed image due to being exposed to the light or the active gas in the environment. Thus, a colorant and an ink composition having a particularly good color, an excellent fastness to light and active gases (NOx, SOx other than the oxidative gas such as ozone, etc.) in the environment and, and having a high solubility is more and more strongly demanded.
Recently, as a phthalocyanine colorant to balance both color and the fastness to ozone and light, the phthalocyanine colorant having a particular sulfinyl group or a sulfonyl group is described in Patent Document 1. Further, in the phthalocyanine colorant described in the corresponding literature, it is described that β-position substitution type (in the case where each of R1 to R16 in the Formula (IV) is set to be the positions 1 to 16, the one having a specific sulfonyl group or sulfinyl group at position 2 and/or 3, position 6 and/or 7, position 10 and/or 11, position 14 and/or 15) as a substitution position of a substituent group has better color and fastness to light and ozone than α,β-position mixed type (there is no regularity in a substitution position of a substituent group).
As a phthalocyanine colorant to balance both color and the fastness to ozone and light, the azaphthalocyanine colorant having a sulfo group and a substituted sulfamoyl group is described in Patent Document 2.